diff --git a/server/src/services/remote-workspace-archive-worker.test.ts b/server/src/services/remote-workspace-archive-worker.test.ts
new file mode 100644
index 00000000000..e608be9aedd
--- /dev/null
+++ b/server/src/services/remote-workspace-archive-worker.test.ts
@@ -0,0 +1,107 @@
+import { createHash } from "node:crypto";
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+const state = vi.hoisted(() => ({ control: undefined as SharedArrayBuffer | undefined,
+  mode: "" as "" | "cpu" | "abort", spawned: 0, exited: 0 }));
+vi.mock("node:worker_threads", async importOriginal => {
+  const actual = await importOriginal<typeof import("node:worker_threads")>();
+  return { ...actual, Worker: class extends actual.Worker {
+    constructor(source: string | URL, options?: import("node:worker_threads").WorkerOptions) {
+      if (state.control && typeof source === "string") {
+        const setup = `const testControl=new Int32Array(workerData.testControl);`;
+        source = source.replace("const archive=", `${setup}const archive=`);
+        if (state.mode === "cpu") source = source.replace("const before = await walk(root, true);", `
+          Atomics.add(testControl,0,1);
+          while(!Atomics.load(testControl,1)) Atomics.add(testControl,2,1);
+          const before = await walk(root, true);`);
+        if (state.mode === "abort") {
+          source = source.replace("const before = await walk(root, true);", `
+            Atomics.store(testControl,0,1);
+            await new Promise(resolve=>{input.signal.addEventListener('abort',resolve,{once:true});if(input.signal.aborted)resolve();});
+            check();
+            const before = await walk(root, true);`);
+          source = source.replace(/await fs\.rm\(scratch,\s*\{\s*recursive:\s*true,\s*force:\s*true\s*\}\);?/, `
+            Atomics.store(testControl,3,1);
+            while(!Atomics.load(testControl,4)) await new Promise(resolve=>setTimeout(resolve,5));
+            await fs.rm(scratch, { recursive: true, force: true });`);
+        }
+        options = { ...options, workerData: { ...options?.workerData, testControl: state.control } };
+      }
+      super(source, options);
+      state.spawned++;
+      this.once("exit", () => { state.exited++; });
+    }
+  } };
+});
+import { captureRemoteWorkspaceDirectory, restoreRemoteWorkspaceArchive, workspaceArchive } from "./remote-workspace-snapshot-archive.js";
+
+describe("workspace archive worker boundary", () => {
+  let root: string, cwd: string;
+  beforeEach(async () => {
+    state.control = undefined; state.mode = ""; state.spawned = 0; state.exited = 0;
+    root = await fs.mkdtemp(path.join(os.tmpdir(), "pc-archive-worker-test-"));
+    cwd = path.join(root, "source"); await fs.mkdir(cwd);
+    await fs.writeFile(path.join(cwd, "saved.txt"), "retained work\n");
+    await fs.mkdir(path.join(cwd, "nested"));
+    await fs.writeFile(path.join(cwd, "nested", "bytes"), Buffer.alloc(1024 * 1024, 42));
+    await fs.chmod(path.join(cwd, "saved.txt"), 0o751);
+    await fs.symlink("saved.txt", path.join(cwd, "link"));
+  });
+  afterEach(async () => {
+    if (state.control) { const control = new Int32Array(state.control); Atomics.store(control,1,1); Atomics.store(control,4,1); }
+    await fs.rm(root, { recursive: true, force: true });
+  });
+  it("preserves exact archive bytes, manifest and restored files across real workers", async () => {
+    const directPath = path.join(root, "direct.pcws"), archivePath = path.join(root, "worker.pcws");
+    const direct = await workspaceArchive({ kind: "capture", cwd, archivePath: directPath });
+    const captured = await captureRemoteWorkspaceDirectory({ cwd, archivePath });
+    expect(captured).toEqual(direct);
+    expect(await fs.readFile(archivePath)).toEqual(await fs.readFile(directPath));
+    const targetDir = path.join(root, "restored");
+    await expect(restoreRemoteWorkspaceArchive({ archivePath, targetDir, expectedManifestDigest: direct.manifestDigest })).resolves.toEqual(direct);
+    expect(await fs.readFile(path.join(targetDir, "saved.txt"), "utf8")).toBe("retained work\n");
+    expect((await fs.stat(path.join(targetDir, "saved.txt"))).mode & 0o777).toBe(0o751);
+    expect(await fs.readlink(path.join(targetDir, "link"))).toBe("saved.txt");
+    expect(createHash("sha256").update(await fs.readFile(path.join(targetDir, "nested", "bytes"))).digest("hex"))
+      .toBe(createHash("sha256").update(await fs.readFile(path.join(cwd, "nested", "bytes"))).digest("hex"));
+    expect(state.spawned).toBe(2); expect(state.exited).toBe(2);
+  });
+  it("runs CPU barriers on eight real workers while an aborted queued capture never spawns", async () => {
+    state.control = new SharedArrayBuffer(5 * 4); state.mode = "cpu";
+    const control = new Int32Array(state.control), controller = new AbortController(), reason = new Error("queued capture cancelled");
+    const captures = Array.from({ length: 8 }, (_, i) => captureRemoteWorkspaceDirectory({ cwd, archivePath: path.join(root, `${i}.pcws`) }));
+    const queued = captureRemoteWorkspaceDirectory({ cwd, archivePath: path.join(root, "queued.pcws"), signal: controller.signal }).catch(error => error);
+    try {
+      await expect.poll(() => Atomics.load(control,0), { timeout: 10_000 }).toBe(8);
+      expect(state.spawned).toBe(8); expect(state.exited).toBe(0);
+      expect(Atomics.load(control,2)).toBeGreaterThan(0);
+      controller.abort(reason);
+      expect(await queued).toBe(reason); expect(state.spawned).toBe(8);
+      Atomics.store(control,1,1);
+      await Promise.all(captures);
+      expect(state.exited).toBe(8);
+      await expect(fs.access(path.join(root, "queued.pcws"))).rejects.toMatchObject({ code: "ENOENT" });
+    } finally { Atomics.store(control,1,1); await Promise.allSettled(captures); }
+  });
+  it("waits for abort cleanup and actual worker exit before rejecting or releasing its slot", async () => {
+    state.control = new SharedArrayBuffer(5 * 4); state.mode = "abort";
+    const control = new Int32Array(state.control), controller = new AbortController(), reason = new Error("owned capture cancelled");
+    let settled = false;
+    const archivePath = path.join(root, "cancelled.pcws");
+    const capture = captureRemoteWorkspaceDirectory({ cwd, archivePath, signal: controller.signal }).then(
+      () => { settled = true; return null; }, error => { settled = true; return error; });
+    try {
+      await expect.poll(() => Atomics.load(control,0), { timeout: 10_000 }).toBe(1);
+      controller.abort(reason);
+      await expect.poll(() => Atomics.load(control,3), { timeout: 10_000 }).toBe(1);
+      expect(settled).toBe(false); expect(state.exited).toBe(0);
+      Atomics.store(control,4,1);
+      expect(await capture).toBe(reason);
+      expect(state.exited).toBe(1);
+      await expect(fs.access(archivePath)).rejects.toMatchObject({ code: "ENOENT" });
+    } finally { Atomics.store(control,4,1); controller.abort(reason); await capture; }
+  });
+});
diff --git a/server/src/services/remote-workspace-snapshot-archive.test.ts b/server/src/services/remote-workspace-snapshot-archive.test.ts
index 8b49be22069..3401d7e1aa7 100644
--- a/server/src/services/remote-workspace-snapshot-archive.test.ts
+++ b/server/src/services/remote-workspace-snapshot-archive.test.ts
@@ -6,7 +6,7 @@ import os from "node:os";
 import path from "node:path";
 import { promisify } from "node:util";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import { captureRemoteWorkspaceDirectory, readRemoteWorkspaceArchiveDirectories, remoteWorkspaceArchiveScript, remoteWorkspaceCaptureFailureMessage, restoreRemoteWorkspaceArchive } from "./remote-workspace-snapshot-archive.js";
+import { workspaceArchive, readRemoteWorkspaceArchiveDirectories, remoteWorkspaceArchiveScript, remoteWorkspaceCaptureFailureMessage } from "./remote-workspace-snapshot-archive.js";
 
 const archiveIo = vi.hoisted(() => ({
   afterChmod: undefined as ((target: string, mode: number) => void) | undefined,
@@ -35,6 +35,9 @@ vi.mock("node:fs/promises", async importOriginal => {
   } };
 });
 
+const captureRemoteWorkspaceDirectory = (input: Omit<Parameters<typeof workspaceArchive>[0], "kind">) => workspaceArchive({ ...input, kind: "capture" });
+const restoreRemoteWorkspaceArchive = (input: Omit<Parameters<typeof workspaceArchive>[0], "kind">) => workspaceArchive({ ...input, kind: "restore" });
+
 const execute = promisify(execFile);
 const env = { ...process.env, GIT_CONFIG_NOSYSTEM: "1", GIT_CONFIG_GLOBAL: os.devNull,
   GIT_AUTHOR_NAME: "Snapshot", GIT_COMMITTER_NAME: "Snapshot", GIT_AUTHOR_EMAIL: "snapshot@example.test", GIT_COMMITTER_EMAIL: "snapshot@example.test" };
diff --git a/server/src/services/remote-workspace-snapshot-archive.ts b/server/src/services/remote-workspace-snapshot-archive.ts
index 3bed12712b1..9af1441c804 100644
--- a/server/src/services/remote-workspace-snapshot-archive.ts
+++ b/server/src/services/remote-workspace-snapshot-archive.ts
@@ -1,8 +1,10 @@
+import { Worker } from "node:worker_threads";
+
 /**
  * A portable, streaming workspace archive. This function is intentionally
  * self-contained: the same implementation runs locally and in a sandbox.
  */
-async function workspaceArchive(input: {
+export async function workspaceArchive(input: {
   kind: "capture" | "restore";
   cwd?: string;
   archivePath: string;
@@ -662,8 +664,72 @@ async function workspaceArchive(input: {
   }
 }
 
+type ArchiveInput = Parameters<typeof workspaceArchive>[0];
+let activeArchiveWorkers = 0;
+const archiveWaiters: Array<() => void> = [];
+
+async function archiveWorkerSlot(signal?: AbortSignal): Promise<() => void> {
+  signal?.throwIfAborted();
+  await new Promise<void>((resolve, reject) => {
+    const start = () => {
+      signal?.removeEventListener("abort", abort);
+      activeArchiveWorkers++;
+      resolve();
+    };
+    const abort = () => {
+      const index = archiveWaiters.indexOf(start);
+      if (index >= 0) archiveWaiters.splice(index, 1);
+      reject(signal!.reason);
+    };
+    if (activeArchiveWorkers < 8) start();
+    else {
+      archiveWaiters.push(start);
+      signal?.addEventListener("abort", abort, { once: true });
+    }
+  });
+  return () => { activeArchiveWorkers--; archiveWaiters.shift()?.(); };
+}
+
+async function runArchiveWorker(input: ArchiveInput): ReturnType<typeof workspaceArchive> {
+  const release = await archiveWorkerSlot(input.signal);
+  try {
+    input.signal?.throwIfAborted();
+    const { signal, ...parameters } = input;
+    const source = workspaceArchive.toString().replaceAll("__vite_ssr_dynamic_import__", "import");
+    const worker = new Worker(`const {parentPort,workerData}=require("node:worker_threads");
+const __name=value=>value;
+const controller=new AbortController();
+parentPort.on("message",()=>controller.abort());
+const archive=${source};
+archive({...workerData,signal:controller.signal}).then(result=>parentPort.postMessage({result}),error=>parentPort.postMessage({error:{...error,name:error.name,message:error.message}})).finally(()=>parentPort.close());`, {
+      eval: true, workerData: parameters, execArgv: [], stdout: true, stderr: true,
+      resourceLimits: { maxOldGenerationSizeMb: 1024, maxYoungGenerationSizeMb: 64, stackSizeMb: 4 },
+    });
+    worker.stdout.resume(); worker.stderr.resume();
+    const abort = () => worker.postMessage("abort");
+    signal?.addEventListener("abort", abort, { once: true });
+    if (signal?.aborted) abort();
+    try {
+      return await new Promise<Awaited<ReturnType<typeof workspaceArchive>>>((resolve, reject) => {
+        let result: Awaited<ReturnType<typeof workspaceArchive>> | undefined, failure: Error | undefined;
+        worker.once("message", (message: { result?: typeof result; error?: Record<string, unknown> }) => {
+          result = message.result;
+          if (message.error) failure = Object.assign(new Error(String(message.error.message)), message.error);
+        });
+        worker.once("error", error => { failure = error; });
+        worker.once("exit", code => {
+          if (signal?.aborted) reject(signal.reason);
+          else if (failure) reject(failure);
+          else if (code === 0 && result) resolve(result);
+          else reject(new Error("remote_workspace_archive_worker_failed"));
+        });
+      });
+    } finally { signal?.removeEventListener("abort", abort); }
+  } finally { release(); }
+}
+
 export function captureRemoteWorkspaceDirectory(input: { cwd: string; archivePath: string; manifestPath?: string; exclude?: string[]; requireNoGit?: boolean; gitSourceRoots?: string[]; signal?: AbortSignal }) {
-  return workspaceArchive({ ...input, kind: "capture" });
+  return runArchiveWorker({ ...input, kind: "capture" });
 }
 
 export async function readRemoteWorkspaceArchiveDirectories(archivePath: string, expectedManifestDigest: string) {
@@ -691,7 +757,7 @@ export async function readRemoteWorkspaceArchiveDirectories(archivePath: string,
 }
 
 export function restoreRemoteWorkspaceArchive(input: { archivePath: string; targetDir: string; expectedManifestDigest: string; signal?: AbortSignal; maxEntries?: number; maxManifestBytes?: number }) {
-  return workspaceArchive({ ...input, kind: "restore" });
+  return runArchiveWorker({ ...input, kind: "restore" });
 }
 
 export function remoteWorkspaceCaptureFailureMessage(error: unknown): string | null {